Effects of molecular interactions on the viscoelastic and plastic behaviour of plasticized poly(vinyl chloride)

✍ Scribed by A Dubault; L Bokobza; E Gandin; JL Halary

• Book ID: 104526736
• Publisher: John Wiley and Sons
• Year: 2003
• Tongue: English
• Weight: 250 KB
• Volume: 52
• Category: Article
• ISSN: 0959-8103
• DOI: 10.1002/pi.1189

✦ Synopsis

Abstract

The mechanical behaviour of plasticized poly(vinyl chloride) in the glassy state was revisited in order to provide some understanding of the properties observed on the molecular scale. Nine samples were investigated, consisting either of pure poly(vinyl chloride) or of plasticized formulations including different amounts of di‐octyl phthalate or benzyl butyl phthalate in the range 5–20 wt%. Presence of the additives resulted in the depression of the glass transition temperature, T~g~, and the main mechanical relaxation temperature, T~α~, as determined by differential scanning calorimetry and dynamic mechanical analysis, respectively. These expected results were related to the plasticizing character of the additives on the long‐range cooperative polymer motions. In addition, a marked reduction of the secondary mechanical relaxation β was observed for additive concentrations equal to or larger than 10 wt%. This antiplasticizing effect was interpreted as the hindrance of main‐chain local polymer motions, due to poly(vinyl chloride)–additive interactions. Occurrence of such interactions was confirmed by mid‐ and near‐infrared measurements. The plastic behaviour of the materials in the glassy state was also examined. Particular attention was paid to the strain‐softening amplitude (difference between yield stress and plastic flow stress), to the percentage of non‐elastic deformation and to the mechanical energy to yield. All these quantities are strongly affected by the chain‐mobility characteristics. Copyright © 2003 Society of Chemical Industry